edit: Dang.... Just saw that @steve w beat me to it
www.garagejournal.com
Golden rule of project estimating....
How many of <unit> will it take?
Double that
Increase unit-of-measure to the next higher
example:
How long would it take you to build this?
Kinda curious if my skills are really as lame as they seem to be. How long would it take you to build this raised bed (excluding filling it), which was my mothers' day gift to my wife? Table saw, cordless Makita circular saw, impact driver, and the normal complement of hand tools. The raised bed...
Golden rule of project estimating....
How many of <unit> will it take?
Double that
Increase unit-of-measure to the next higher
example:
- Guesstimate: 2 hour project
- Double the 2 - Now it's 4
- Next higher unit of measure from hours - Days
- So.... This project will take 4 days

